Variable-capacity compressor



June 17, 1930. RlESNER 1,764,646

' VARIABLE CAPACITY COMPRESSOR Filed July 27, 1929 I l W 3 c 6 w B 1.:

Ir a 14 i2 2 26 55' a j 55 l d MIGHAELRJESNER INVENTOR ATTORNEY I Patented June 17, 1930 UNITED STATES .PATENTIOFFICE irrcnanr. nmsnnn, or cmcmimm, .onro, ASSIGNOR 'ro womnmegron rum AND mcnmnmr oonronnrron, or NEW YORK, 11. Y.,' A conronarrozr'or waernm Application fi ed July 27,

' The primary object of the invention 'is to provide an apparatus of this type which will be economical in operation, provide a relatively high compressor eificiency and one which will be relatively simple in construction.

In accordance with the present invention 5 there is combined a plurality of unloadingdevices and clearance chambers, which cooperate to unload and load the cylinder of the compressor in such a way as to secure a larger number of unloading steps than the number of unloadin devices used, thus reducing the number 0 unloading devices on-the cylinder and making the cdmpressor itself less complicated'in construction.

The present invention embodies the use of a plurality 'of clearance chambers of unequal capacity' connected to the cylinder through the unloading devices in such manner, that by theopening of one clearance chamber" to-the cylinder one end of the cylinder may be partly unloaded; the opening of the other clearance chamber to the cylinder-will wholly unload one end of the cylinder; the opening of both clearance chambars to the cylinder will partly unload one end of the cylinder and wholly unload the other end, whereas when the clearance chambers are both open to the cylinder and to each other the compressor will be wholly unloaded or operated at zero capacity. Together with the above arrangement of clearance chambers, the present invention ineludes suitable pressure operated control apparatus to control operation of said unloading devices in proper sequence at proper times to permit operation of the compressor under various predetermined percentages of its full capacity in accordance with the unloading sequence just above set-out.

With these and other objects in view as 50 may appear from the accompanying speci- I A is controlled by the unloading mechanism 'vAnIABLE-cArAc rY corrrnnsson 1929., Serial No. 881,596],

fication, the invention consists in various features of. construction andcombination of parts, which will be first described in connection with the accompanying drawing, Y which shows in section, in a semi-di'agram- 5 matic manner; a variable capacity com-pressor constructedpin accordance with this in-. vention, and the features forming the invention. will be specifically pointed out in the claims. 4

Referrin more particularlyto the drawings A is the compressor cylinder in which the piston,B reciprocates'. The piston B is driven or reciprocated, through the piston rod 0 in .any suitable manner. It is to be understood that the compressor cylinder structure'is provided with suction and discharge valves, of approved type, at the crank and headends of the cylinderA as is usual in the construction of double acting air or gas compressors of approved types. 7 The c linder A. has a clearance'chamber 1 associated therewith which opens out through a port 2*withthehead end of the cylinder and this-clearance chamber 1 is of sufiicient capacity to wholly unload-the head end of the cylinder when the unloadingdevice 3 is operated to unseat the valve 4: and

open the clearance chamber-.1 to the head. end of the cylinderA. A second clearance 80 chamber 5 is provided which opens through c a port-6 into the crank end of the cylinder A and the capacity of this clearance chamber 5 is such as to only partly unload the crank end of the cylinder; preferably unload the crank end'50% of its capacit which is 25% of the total capacity of t e compressor. The communication between the clearance chamber 5 and the crank end of the cylinder 7 which includes the valve 8. .l The clearance chambers 1 and 5 are open to communication one with' the other through a port 9 formed suitably in the partition 10 which divides orseparates the two clearance chambers. The port 9, like the ports 2 and 6 is controlled by a pressure operated unloading mechanism 11.

The pressure operated unloader mecha aj nisms 3, 7 and 11 are all alike and are similar to those disclosed in my prior Patent No. 1,636,439 and they are controlled in their operation by governor mechanism such as that disclosed in my prior Patent No. 1,579,781. a

More specifically, the pressure operated unloading devices include the pistons 12 which are mounted upon the stems 13. The various valves 4, 8 or 14 are connected to the valve stems 13 and are seated or unseated by movement of the respective pistons 12. The pistons 12 reciprocate in the cylinder structures 15 and are moved by fluid under pressure, the admittance of which, into the cylinders, is controlled by the governor mechanism as hereinafter more specifically described. The fluid under pressure is admitted through the governor into the cylinders 15 inwardly of the pistons 11 and forces them outwardly for unseating the valves 4.

In operation, when the pressure in the receiver (not shown) reaches a predetermined degree, the control apparatus D which is similar to that shown in my prior Patents 1,579,781 and 1,704,343 will operate and move the piston 22 of the governor or control mechanism so as to open communication between the pipe 21 which admits the pressure fluid into the cylinder 20 and the pipe 23. The fluid under pressure passes through the pipe 23, the cylinder 24 of the intermediate valve structure 25 and through the pipe 26 into the cylinder 15 of the pressure operated unloading device 7 causing the outward movement of the piston 12 and the unseating of the valve 8. This opens the crank end of the cylinder A to the clearance chamber 5 and permits a unloading of the crank end of the cylinder and a consequent operation of the compressor at 75% of its capacity.

Upon a further increase in receiver pressure, the piston 22 moves farther within the cylinder 20 and opens the pipe 21 to the port 27 and permits the pressure fluid to pass from the port 27 through thepipe 28 into the enlarged portion 29 of the cylinder 24 of the intermediate valve 25. The pressure fluid entering the enlarged portion 29 of the cylinder 24 acts on the piston 30 of the intermediate valve 29 and owing to the increased area of the piston 30 over the piston sections 31 and 32 of the plunger 33 of the valve 25, moves the plunger so as to cut off the communication between the pipes 23 and 26 and permit the fluid under'pressure, which is in the cylinder 15, to bleed therefrom and exhaust through the exhaust pipe 34 of the intermediate valve 25. The port 27 also has a pipe 35 connected thereto so that at the same time that the pressure fluid is admitted into the enlar ed portion 29 of the cylinder 24, in front 0 the piston 30, the air under pressure will be admitted into the cylinder 15 of the unloading mechanism 3 back of piston 12 thereof to move this piston and unseat the valve 4 for opening the head end of the cylinder A to the clearance chamber 1. This wholly unloads the head end of the cylinder and permits the compressor to operate at 50% of its full capacity, since, when the pressure fluid was permitted to exhaust from the cylinder 15 of the unloading device 7 the. pressure back of the piston 12 of the unloading device 7 would seat the valve 8 and cut off" communication between the crank end of the cylinder and the clearance chamber 5.

Upon further increase in receiver pressure the port 35 is opened to communication with the pressure fluid entering the cylinder 20 of the controlling or regulating valve structure and the port 35 permits the pressure fluid to enter the enlarged portion 29 of the cylinder 24 in front of the piston 30. Owing to the increased area of the outer end of the piston 30, acted upon by the pressure fluid, together with the pressure applied by the spring 36, the plunger 33 will be forced to the left, in the drawings, and again open communication between the pipes 23 and 26 to permit the pressure fluid to be admitted to the cylinder 15 of the unloading device 7 in front of the piston 12 thereof to unseat the valve 8 and again open the' clearance chamber 5 to the crank end of the cylinder, providing a reverse step in the unloading operation of the compressor. At this time the valve 4 will also be held unseated through admittance of the pressure fluid to the unloading mechanism 3 through the pipe 35 and thus the head end of the cylinder A of the compressor will be wholly unloaded and the crank end will be unloaded 50% which will permit the compressor to operate at 25% of its capacity.

Upon a further increase of receiver pressure the port 37 is opened to receive the fluid under pressure from the cylinder 15 of the unloading mechanism 11 for moving the piston 12 thereof to unseat the valve 14 and open the clearance chamber .1 to the clearance chamber 5 which in turn opens the head end of the cylinder A to the-crank end of, the cylinder A and permits the by-passsame proportion of its full capacity as those in which it is unloaded; e., upon decrease in receiver pressure the ressure is relieved against the piston 12 of t e unloading mechanism 11, through the return movement of the piston 22 by means of the governor mechanism such as disclosed in my prior Patent tween the clearance chambers 1 and 5 the of t e piston 12, the relatively low pressure which is admitted to the cylinder through combination with a cylinder of a clearance 1,579,781 and the pressure fluid behind thepiston 12 is permitted to bleed from the cylinder 15 back into the cylinder and exhaust through the exhaust openings 40 in the cylinder 20. The exhaust openings 40 are open to the atmosphere or to any suitable erations prevented by the piston 22. When ressure is relieved from' the inner side the pipe 41, together. with the action of the spring/l2 will move the piston 12 to seat the valve 14 and cut off the communication bethereby permitting the compressor to oper ate at of its full capacity.

The relatively low pressure fluid which is admitted to the cylinder 15 of the unloading mechanism 11 and which is also admitted to the cylinders 15 of the unloading devices 3 and 7 maybe supplied from an intermediate stage or inter-stage cooler.

A further decrease in. receiver pressure will cut off the communication between the cylinder 15 of the unloading mechanism 7 and the cylinder 20 by the relief of the pressure from the'outer or right hand endof the piston .30 of the plunger 33 and will cause the plunger to be moved by the pres- V sure entering the cylinder 24 through the pipe 28 efliciently to permit the pressure fluid back of the piston "12 to bleed out I pressure fluid from the cylinder 15 of-the partial unload ng of the crank end of thethrough the cylinder 24 and its exhaust 34.

. its capacity.

Upon a further decrease in receiver pressure theport 27 will be opened to the exhaust 40 which will the yalve 4 through the bleeding of the unloading mechanism 3. At the same time at which the pressure fluid is permitted to bleed from the unloading mechanism 3, the plunger 33 will be relieved of pressure against its piston 30 through the pipe 28 and,

the plunger will be urged or moved by the spring 36 and the action of the pressure fluid against the piston :32 of the plunger into position to perm't the pressure fluid to again enter the cylinder 15 of the unloadin mechanism 7 and 0 en the valve 8 to al ow the cylinder and-the consequent operation of a compressor at 7 5% of its capacity.

A further decrease in receiver pressure will cause the cutting ofi' of communication between the pipes 23 and 21 and will permit thebleedingof the pressure'fluidsfrom the cylinder 15 of the unloading device 7 back permlt the seating ofthrough the pipe 23 and to the cylinder 20 and out of the exhaust 40 thereof thereby permitting the seating of the valve 8 and the operationof a compressor at its full capacity.

It will be understood that the invention is not to be limited to-the specific construction or arrangement of parts shown by the fact that these may be modified widely with-g in the invention as defined by the claims.

What is claimed is:

1. In a variable capaclty compressor, the

chamber for wholly unloading one end of the cylinder, a second clearance chamber to partly unloading the other end of the cyl- 1nder, a plurality of pressure operated unloading devices each acting to partially unlso load the cylinder, and pressure controlled governor mechanism including means for successively brmgmg one of said devlces 1nto action a plurality of times during each of the cylinder unloading and loading operations.

2. Ina variable capacity com ressor, the combination with a cylinder, 0 two clearance chambers one having greater'capacity than the other, the dividing wall of said chambers having an opening to permit communication between the cylinders for wholly unloading the compressor, pressure operated unloading devices for controlling communi cation of said chambers with said cylinder and with each other, and ressure controlled governor mechanism inc uding means for successively bringing one of said devices into action a plurality of times during each of the cylinder unloading and loading operations.

3. In a variable capacity compressor, the combination with acylinder, of a clearance chamber for wholly unloading one end of the cylinder, a second clearance chamber for partly unloading theother end of the cylinder, the dividing wall of said chambers hay;

ing an opening to permit communication he tween the cylinders for wholly unloading the compressor, a plurality of pressure operated unloading devices each acting to partially unload the cylinder, and for controlling communication-of said chambers with each other, and pressure controlled governor "mechanism including means for successively bringing one of said devices into action a plurality of times duringi each of the cylinder unloadin and loading operations.

4:- Ina varia lecapacity compressor, the combination with a cylinder, of a clearance chamber for wholly unloading onoend of the cylinder, asecond clearance chamber-for partly unloading the other end of the cylinder, a pressure operated unloading device for each of said chambers acting to partially unload the cylinder, and a pressure controlled governor mechanism including means for bringing the unloadingdevice associated with said second clearance chamber into action a plurality of times during each of the cylinder unloading and loading operations.

5. In a variable capacity compressor, the combination with a cylinder of a clearance chamber for wholl unloading one end of the cylinder, a secon clearance chamber for partly unloading the other end of the cylinder, the dividing wall of said chambers provided with an opening to permit communication of the chambers for wholly unloading the cylinder; a pressure operated unloading device for each of said chambers actingto partially unload the cylinder, a pressure operated unloading device acting to control said chamber communicating opening, and

a pressure control governor mechanism in-v eluding means for brmging the unloading device associated with the second clearance chamber into action a plurality of times during each of the cylinder unloading and loading operations.

6. In a variable capacity compressor, the

combination with a cylinder of a clearance chamber for wholly unloading one end of cylinder, a second clearance chamber for partly unloading the other end of the cylinder; the dividing wall of said chambers provided with an o ening to permit communication of the cham rs for wholly unloading the cylinder; a pressure operated unloading device for each of said chambers acting to partially unload the cylinder; at pressure operated unloading device acting to control said chamber communicating opening, and a pressure controlled governor mechanism includin a pressure operated intermediate valve or bringing the unloading device associated with said second clearance chamber successively into action a plurality of times during each of the complete unloading and loading operations of the cylinder.

7. In a variable capacity compressor the combination with a cylinder, of means for completely unloading and loadin the compressor in successive steps of pre etermined percentages of the cylinder capacity, said earance chamber for means including a c partially unloading one end of the cylinder, a pressure operated unloading device controlling communication between the cylinder and said clearance chamber, and a pressure controlled governor mechanism including means for bringing said unloading device successivel into action a plurality of times during eac complete unloading and loading operation of the cylinder.

8. In a variable capacity compressor the combination with a cylinder, of means for completely unloading and loading the compressor in successive steps of predetermined percentages of the cylinder capacity, said means including a clearance chamber for partially unloading one end of the cylinder, 

